The subject matter disclosed herein relates to a device for use in a district steam heating system, and in particular to a device that recycles condensate to reduce consumption by end users and reduce discharges into sewer systems.
In large metropolitan areas, it is not uncommon for a central boiler system to be used to generate heat for multiple facilities in the surrounding area. This heating system is sometimes referred to as district heating. The steam is transported via insulated pipes to subscribing buildings, which purchase the steam from the steam utility. Similar to an electric meter, a steam meter measures the amount of steam used by a particular building and the building owner is charged on a periodic basis.
Some of the facilities that receive steam from the district heating system distribute the steam through the building steam-based space heating system, other facilities convert the steam into hot water in tube and shell heat exchangers. In the latter system, the hot water is then distributed by electrically driven pumps through-out the building for space heating and domestic hot water service. After the steam is utilized in either application, the resulting condensate is typically discharged to the city sewer system. In order to reduce the condensate temperature from 215-220 F. to about 150 F. (a typical city sewer requirement) the condensate is mixed with cold potable water.
The routing of the condensate into the sewer system is a convenient means for disposing of the condensate. However, the facility owner or the district heating system provider is charged a fee based on the amount of waste, including condensate water, that is discharged into the sewer system. Further, since cold water is mixed with the condensate to reduce the temperature, usable energy is wasted and discharge fees are increased.
Accordingly, while existing district heating systems are suitable for their intended purposes a need for improvement remains, particularly in reducing the amount of condensate discharge and in increasing the extraction of energy from the delivered steam.